This invention relates to personal computer (PC) systems and in particular to such systems where two or more people both see the same display and need to point out something on the display.
In some known PC games, two separate game controllers can be operated for the same screen. The standard game controller port supports two mice and a separate Y connector can be used. A standard PC input port does not support multiple game controllers. On the screen there can be different "cursors" or equivalent pointing devices for each player. Some multi-user games can be played on networks, in which case the application must support network use.
In teleconferencing applications, local and remote users can see at the local PC screen, multiple windows where remote and local PC screens are presented. One window can show one separate application and there can be only one active cursor at a time.
In classroom applications there can be multi-user screen sharing, and each PC including the teacher's PC require special controllers.
In a help desk application a customer contacts a help desk advisor via a data network and the same image can be viewed by the advisor at a support PC and the customer at a customer PC. The delay in transmitting graphic information between such computers is particularly troublesome when the computers are equipped with an input device requiring visual feedback, such as a mouse, as an operator's physical movement is not then keyed directly to the cursor movement. U.S. Pat. No. 5,168,269 attempts to overcome this problem by providing immediate visual feedback in the form of a second cursor, a Dynamic Temporary Dual Cursor, which is provided on the screen of the one PC along with the cursor transmitted from the other PC and which is moved in quick synchronisation with the input of the mouse input device. In time the transmitted cursor coincides with and merges with the Dynamic Temporary Dual Cursor.
Two people viewing one display, may be the PC "owner" (Host User) and a customer viewing the same VDU (Visual Display Unit) and, conventionally, there would be one mouse, operated by the Host User, for controlling the position of a cursor on the display. When it is necessary for the Guest User to, for example, select one item from of a multiple choice menu of a particular application, hitherto the Guest User has either pointed to the display with a finger or pen, for example, and/or communicated their choice verbally. If the pointing approach is employed, the screen of the display can become soiled with fingerprints or scratches. The verbal approach can be slower than the pointing approach and may involve misunderstandings between the Host User and the Guest User and thus incorrect selections.
It is an object of the present invention to overcome the aforementioned disadvantages in a system where two people are viewing the same VDU, as referred to in the previous paragraph.